1) I really can't think of it. My head is broken. I can only explain it reluctantly: every number adds up to an even number, so only A fits.

2) I began to think about doing something. The first few adjacent items have a difference of 1 1 or-1 1, and the last two items have a difference. Later, it was found that there were two 15, so I thought that 16 could be the fourth power of 2 or the second power of 4, and I thought of 27 from 26, which is the third power of 3. So the terms are 2 4- 1, 3 3- 1, 4 2- 1, 51,(6 0- 1), so () =

3) The difference between11step seems to be 4458 15 ()

0 1 3 7 ( 15)

1 2 4 (8)

So () =30

4) The series is expanded, indicating that it is either a product series or a multiple, but this problem is obviously more like a product series, and the law is C=A*B+2, so () = 18* 146+2=2630.

5) This question is too simple. Maybe because she has both decimals and fractions, as well as fractions with large numerator and denominator, you are confused. But if you look at 5 1/68, it can be reduced to 3/4. The number of each homogenized component becomes 1/2 2/3 3/4 4/5 (5/6).